Windows Developer Documentation

The Windows Hello companion device framework allows external devices (e.g., USB peripherals, smartphones, NFC tags, or fitness bands) to act as authentication companions for a Windows 10 desktop. This enhances the user authentication experience, especially when the desktop lacks native biometric hardware like a camera or fingerprint reader.

Important Note: The API for the Windows Hello companion device framework is deprecated in Windows 10, version 2004.

For implementation details and code samples, refer to the Windows Hello companion device framework Github repository.

This guide provides a collection of best practices for building Windows applications designed for a diverse user base. The guidance is categorized into several key areas to ensure high-quality software:

• User experience (UX): Improving the look, feel, and usability of applications.
• Performance and fundamentals: Optimizing app performance and resource utilization.
• Operating system / hardware optimization: Optimizing packaging and distribution across various hardware configurations.
• Application discovery and management: Improving how users discover, install, update, and uninstall applications.
• Accessibility: Building inclusive and accessible experiences.
• Security and privacy: Mitigating security risks and meeting user privacy requirements.

Universal Windows Platform (UWP) is a way to create client applications that run across a wide variety of Windows 10 and Windows 11 devices, including desktop PCs, Xbox, HoloLens, Surface Hub, and IoT devices.

Note for new developers: While UWP is still supported, Microsoft recommends using the Windows App SDK and WinUI for new Windows app development projects.

Recall is an AI-assisted feature in Windows that uses Microsoft Foundry on Windows to allow users to search through past activity via screen snapshots.

To ensure your application integrates effectively with Recall, you should use the UserActivity API. This API allows your app to provide deep links, enabling users to jump directly back to specific content within your application from a Recall snapshot using the relaunch button.

To understand the current landscape of Windows development, you can explore various technologies including WinUI, .NET MAUI, React Native, Blazor, and Progressive Web Apps (PWAs).

For a detailed review, you can watch the Windows Dev Chat: Choosing your ideal dev platform or refer to the overview of app development options.

Windows on Arm supports native Arm64 apps, as well as unmodified x86 and x64 apps via emulation. While emulation provides compatibility, building Arm-native apps is required for optimal performance, responsiveness, and battery life.

Key Architectures:

• Arm64 (AArch64): The 64-bit architecture used by modern Windows on Arm PCs. Native apps run here without emulation.
• Arm32 (Arm): The 32-bit architecture. Windows on Arm can run Arm32 apps.
• x86/x64: Traditional Intel/AMD architectures. These run on Arm devices via emulation (Windows 10 supports x86; Windows 11 supports x86 and x64).

The Marble Maze sample utilizes several DirectX technologies to handle different rendering requirements:

• Direct3D 11.1: Used for rendering 3D game assets, such as the marble and the maze. It provides high performance and maximum control over rendering.
• Direct2D: Used for drawing 2D game assets, such as menus.
• DirectWrite: Used for high-quality text rendering (e.g., timers).
• Windows Imaging Component (WIC): Used for low-level digital image handling and 2D asset loading.

The Windows Package Manager (WinGet) includes a built-in Model Context Protocol (MCP) server. This server exposes WinGet's core functionality to AI agents and development tools, allowing them to intelligently assist with software management tasks.

Key capabilities provided to AI agents include:

• Discovering available packages: Agents can search the WinGet repository to find accurate, up-to-date information about software, including package IDs, versions, publishers, and installation options.
• Installing packages: Agents can identify appropriate packages and assist with the installation process, providing commands or initiating installations (typically requiring user approval).

WinUI and Windows App SDK apps can interoperate with the Visual Layer to create advanced effects that are not available via standard XAML APIs alone. This interop allows you to apply composition-based effects to existing XAML content without restructuring your entire UI.

Common use cases include:

• Brush effects (blur, frosted glass)
• Dynamic lighting
• Scroll-driven animations and parallax
• Automatic layout animations
• Pixel-perfect drop shadows

When converting a Windows desktop app to a UWP app using the Desktop Bridge, you can use built-in tests to ensure the app is optimized for its new packaging format (.appx or .appxbundle).

Tests are categorized into two types:

1. Required tests: These determine the pass/fail criteria for Microsoft Store onboarding. Your app must pass these to be certified.
2. Optional tests: These are informational only and do not affect Store onboarding. They are intended to help you improve app quality and compatibility (e.g., for Windows 10 S).